dt-bindings: spi: Convert imx lpspi to json-schema

Convert the i.MX LPSPI binding to DT schema format using json-schema
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1592281575-32708-4-git-send-email-Anson.Huang@nxp.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/spi-fsl-lpspi.txt

-* Freescale Low Power SPI (LPSPI) for i.MX
-
-Required properties:
-- compatible :
-  - "fsl,imx7ulp-spi" for LPSPI compatible with the one integrated on i.MX7ULP soc
-  - "fsl,imx8qxp-spi" for LPSPI compatible with the one integrated on i.MX8QXP soc
-- reg : address and length of the lpspi master registers
-- interrupt-parent : core interrupt controller
-- interrupts : lpspi interrupt
-- clocks : lpspi clock specifier. Its number and order need to correspond to the
-	   value in clock-names.
-- clock-names : Corresponding to per clock and ipg clock in "clocks"
-		respectively. In i.MX7ULP, it only has per clk, so use CLK_DUMMY
-		to fill the "ipg" blank.
-- spi-slave : spi slave mode support. In slave mode, add this attribute without
-	      value. In master mode, remove it.
-
-Examples:
-
-lpspi2: lpspi@40290000 {
-	compatible = "fsl,imx7ulp-spi";
-	reg = <0x40290000 0x10000>;
-	interrupt-parent = <&intc>;
-	interrupts = <GIC_SPI 28 IRQ_TYPE_LEVEL_HIGH>;
-	clocks = <&clks IMX7ULP_CLK_LPSPI2>,
-		 <&clks IMX7ULP_CLK_DUMMY>;
-	clock-names = "per", "ipg";
-	spi-slave;
-};

Documentation/devicetree/bindings/spi/spi-fsl-lpspi.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/spi-fsl-lpspi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale Low Power SPI (LPSPI) for i.MX
+
+maintainers:
+  - Anson Huang <Anson.Huang@nxp.com>
+
+allOf:
+  - $ref: "/schemas/spi/spi-controller.yaml#"
+
+properties:
+  compatible:
+    enum:
+      - fsl,imx7ulp-spi
+      - fsl,imx8qxp-spi
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: SoC SPI per clock
+      - description: SoC SPI ipg clock
+
+  clock-names:
+    items:
+      - const: per
+      - const: ipg
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/imx7ulp-clock.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    spi@40290000 {
+        compatible = "fsl,imx7ulp-spi";
+        reg = <0x40290000 0x10000>;
+        interrupt-parent = <&intc>;
+        interrupts = <GIC_SPI 28 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&clks IMX7ULP_CLK_LPSPI2>,
+                 <&clks IMX7ULP_CLK_DUMMY>;
+        clock-names = "per", "ipg";
+        spi-slave;
+    };